Stationary and progressive waves

Question 1

What is a stationary wave?

Answer 1

a vibration of a system in which some particular points remain fixed while others between them vibrate with the maximum amplitude.

Question 2

What is the fundemental mode of vibration?

Answer 2

consists of a single loop that has a node at either end

Question 3

What is a node

Answer 3

a point of no displacement

Question 4

Where is the maximum amplitude?

Answer 4

midway between the node this is the antinode

Question 5

What does the distance between adjacent nodes =?

Answer 5

1/2 wavelength (lamba)

Question 6

What can be said about the energy transfer in a stationary wave?

Answer 6

stationary waves that vibrate freely do not transfer energy to their surrounding

Question 7

Where is the maximum energy in a stationary waves?

Answer 7

antinode max vibration

Question 8

What is superpoistion?

Answer 8

• waves pass through eachother
• at instant waves cross each wave combine
• principle of superpositon
  
  • when two or more waves cross, the resultant displacemetn equals the vector sum of the individual displacements

Question 9

When is the phase difference 0 or 180

Answer 9

0 if two particles are between adjacent nodes or separated by an even number of nodes

180 degrees (pi radians) if two particles are separated by an odd number of nodes

Question 10

What is the difference between frequency in stationary and progressive waves?

Answer 10

stationary - all particles except those at the nodes vibrate at the same frequency

progressive waves - all particles vibrate at the same frequency

Question 11

What is the difference between amplitude in stationary and progressive waves?

Answer 11

stationary - the amplitudes varies from 0 at the nodes to a maximum at the antinode

progressive - the same for all particles

Question 12

What is the difference between phase difference between two particles in stationary and progresive waves?

Answer 12

stationary = mπ where m is the number of nodes between to particles

progressive = 2πd/λ, d = distance apart

Question 13

Suggest how stationary waves are formed in a microwave?

Answer 13

waves superpose produce 1 ovarall standing wave

refelect off wall interfere and supperpose

Question 14

What part of the microwave melts the chocolate?

Answer 14

the anti node amplitude is greatest therefore energy is greatest

Question 15

Why do microwaves have rotating plates?

Answer 15

position of the anti node is constantly changs therefore the food is cooked evenly

Question 16

When are waves exactly in phase and exactly out of phase?

Answer 16

• in phase
  
  • sample displacement and velocity
  • phase difference of zero or a multiple of 360
• out of phase
  
  • odd-number multiples of 180